I have a computer that's resetting every second... Literally. When It is powered-on it continually spins up the fans, hdds, lights leds on the motherboard, chasis, and then cuts dead. All within one second over and over and over until power is removed. First impression was that something may have been shorting out . I've swapped out many of the parts and it still does the same. Only things left are the motherboard and power supply, no spares to swap though. Any Ideas??? If I'm stuck buying new hardware do I get the PSU or motherboard first? Thanks.
Specs:
X6 Thubian
MSI 870A Fusion
Crossfire HD 5750s
3 Hitachi HDDs
2 Mushkin ddr3 dimms
OCZ 600 watt PSU

The rebate is just $10, even without it the PCP is a good deal. I'm not so sure if it makes much difference whether the PSU is super quiet or not if the rest of your build isn't geared towards quietness. In any case the PCP is quiet unless you really stress it. At common loads you'll be fine.

Which Silverstone is that? You don't really need a 700W unit anyway, 600W is already "future proof" enough (bear in mind though that power consumption tends to go down these days).